Poor grip when driving down road

I would first make sure that all four tires are correctly inflated, have good tread and no signs of uneven tread-wear. I bet they are fine, but check that first.

Otherwise, what I think is happening is your car needs front and rear shocks or struts. Your tires feel like they are floating because they are: when you hit any kind of bump, the coil springs absorb the impact and return the energy upward. The shock absorbers are there to absorb that returned energy. When the shocks (or struts) fail, the car loses full contact with road because the car is in effect bouncing.